you have ONE table with 500 columns!?!?

how big would 1 row be? if it is more then one oracle block size you will not be able to store the row using one block. This is not ideal but happens a lot.

first try to break up the table in to smaller tables and link with foreign keys. If this is not possiable then you must partitioin the table. find a logical grouping of the data and partition the table along these lines.

Andrew
OCP